rotationalEntropyLoss.h

// $Id: rotationalEntropyLoss.h,v 1.2 2006/05/21 18:15:28 anker Exp $
// Molecular Mechanics: SLICK force field, rotational entropy loss

#ifndef BALL_MOLMEC_SLICK_SLICKROTATION_H
#define BALL_MOLMEC_SLICK_SLICKROTATION_H

#include <stack>

#include <BALL/SCORING/COMMON/scoringComponent.h>
#include <BALL/DATATYPE/hashSet.h>
#include <BALL/DATATYPE/hashGrid.h>

namespace BALL
{

  class RotationalEntropyLoss
    : public ScoringComponent
  {

    public:

    enum AlgorithmType
    {
      ALGORITHM__GUESS = 0,
      ALGORITHM__DATABASE = 1
    };

    enum CalculationMethod
    {
      CALCULATION__ORIGINAL = 1,

      CALCULATION__BOEHM = 2,

      CALCULATION__GLYCOSIDIC_BONDS = 3,

      CALCULATION__FROZEN_GLYCOSIDIC_BONDS = 4,

      CALCULATION__GLYCOSIDIC_CONTRIBUTION = 5
    };

    struct Option
    {
      static const char* ROT_BIND_OFFSET;

      static const char* ROT_GRID_SPACING;

      static const char* ROT_ALGORITHM;

      static const char* ROT_METHOD;

      static const char* VERBOSITY;

    };

    struct Default
    {

      static const float ROT_BIND_OFFSET;

      static const float ROT_GRID_SPACING;

      static const Size ROT_ALGORITHM;

      static const Size ROT_METHOD;

      static const Size VERBOSITY;

    };


    RotationalEntropyLoss()
      ;

    RotationalEntropyLoss(ScoringFunction& sf)
      ;

    RotationalEntropyLoss(const RotationalEntropyLoss& fr)
      ;

    virtual ~RotationalEntropyLoss()
      ;



    const RotationalEntropyLoss& operator = (const RotationalEntropyLoss& fr)
      ;

    virtual void clear()
      ;



    bool operator == (const RotationalEntropyLoss& fr) const
      ;



    virtual bool setup()
      ;



    virtual double calculateScore()
      ;


    private:

    /*_ All possible rotatable bonds.
    */
    std::vector<const Bond*> rotatable_bonds_;

    /*_ All glycosidic bonds.
    */
    HashSet<const Bond*> glycosidic_bonds_;

    /*_ The number of rotatable bonds (i. e. rotatable_bonds_.size()).
    */
    Size N_rot_;

    /*_ A vector of bool indicating which of rotatable bond was frozen upon
     * binding.
    */
    std::vector<bool> is_frozen_;

    /* A flag defining which algorithm should be used for finding
     * rotatable bonds
    */
    Size algorithm_type_;

    /* The percentages of nonlipophilc heavy atoms on each side of the bond
     * (named P(r) in the paper).
    */
    std::vector< std::pair<double, double> > heavy_atom_fractions_;

    /*_ This hash grid contains all receptor atoms. We need it for obtaining
     * those ligand atoms that are close to the receptor.
    */
    HashGrid3<const Atom*>* grid_;

    /*_ The spacing of the grid_.
    */
    float grid_spacing_;

    /*_
     */
    Molecule* receptor_;

    /*_
     */
    Molecule* ligand_;

    /*_
     */
    float bind_distance_offset_;

    /*_
    */
    Size calculation_method_;

    /*_ The fresno atom types that are stored in the fresno force field
    */
    HashMap<const Atom*, Size> fresno_types_;

    /*_ A simple DFS algorithm for identifying rings (i. e. cycles) of the
        molecule.
    */
    void cycleDFS_(const Atom* atom,
        HashSet<const Atom*>& visited,
        HashSet<const Bond*>& tree,
        std::stack<const Bond*>& possible_cycle_bonds,
        HashSet<const Bond*>& cycle_bonds,
        int& cycle_count)
      ;


    /*_ A simple DFS implementation for counting heavy (as defined by
     * Rognan et al.) atoms.
    */
    void heavyAtomsDFS_(const Atom* atom, const Bond* bond,
        HashSet<const Atom*>& visited,
        int& heavy_atom_count, int& nonlip_heavy_atom_count)
      ;
    
    /*_ Find out which bonds are still frozen
     */
    void updateFrozenBonds_()
      ;
    
    /*_
     */
    bool frozenBondsDFS_(const Atom* atom,
        HashSet<const Atom*>& visited)
      ;
  };

} // namespace BALL

#endif // BALL_MOLMEC_SLICK_SLICKROTATION_H

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